Tube Preamps Should Have This Feature

Schiit Frea+

The Schiit  Freya + will do just that, see below:

Mike

Whisper-Silent Tube Stage—With Tube Shutdown

''Now, you can enjoy a tube preamp without the hiss and hum of classic designs. Freya+ offers super-quiet tube modes with DC heaters and semi-circlotron, noise-cancelling output stages. Better yet, the tubes turn off when you’re not using them! That’s right, both the tube heater and high voltage rails go away when not in use, so you can preserve lifetime of costly tubes.'' 

I have literally never hesitated to turn on my system. If you can’t afford new tubes, spend less on groceries.

and obtw, the architecture of a passive pre it totally different.  You are asking for 2 totally different components.

"casual listening for a short time"

Your system is going to sound darn good 2 minutes after you turn it on. Try it. Play something favorite, involving I bet. Wait 30 minutes, play again. How much ’More’ involving?

The practice of waiting 20, 30 minutes, (I do it) we convince ourselves, for me it’s why not, but I go cold often enough? Someone coming over, oh helllll yes, warm it up!!!!!!!!!!!

@dweller 

I think that you're worrying way too much about tube wear. Life is short; just use it and be happy.

Agree that life’s too short to stress about such things, especially with regard to a preamp where tubes tend to last pretty long and are relatively cheap to replace.  Music soothes the soul even if it’s just for 30 minutes, so just do it!

The Freya is an excellent choice and does solve this problem. I have one and primarily listen to the buffered, solid state stage for a couple reasons. I will disagree with @elliottbnewcombjr and say that the tube state does not reach its potential for 20-30 minutes, and is nothing special until then. Mine is on all of the time, and occasionally I listen to the tubes, but not often due to the warmup requirements.

I am in search of a new preamp and have trialed a couple solid state designs. I am not opposed to tubes, but would like one that I could just leave on all the time that would not burn through a lot of tubes, and also would not heat my house. Are there tube preamps that you can just leave on all the time and expect to get reasonable tube life?

Find something else to worry about!

How do I know when my tubes need replacing?

Power tubes like EL34's and KT88's are good for about 2500 hours or more. But may go longer in an amplifier with a conservative design. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours. So you get years and years of enjoyment. Using a tube tester may or may not tell you if you need a replacement. The best approach is to buy a new set of tubes, and install them. If they don't sound a lot better, put in the old ones and suck every bit of life out of them.

I am not opposed to tubes, but would like one that I could just leave on all the time that would not burn through a lot of tubes, and also would not heat my house. Are there tube preamps that you can just leave on all the time and expect to get reasonable tube life?

@zlone Linear Tube Audio preamps are excellent and have loooong tube life due to their David Berning ZOTL design, and the tubes are also cheap to replace.  They’re also excellent headphone amps if you swing that way.  Definitely worth a look and plenty of reviews out there that’ll give you more info.  Hope this helps. 

Thanks to all for responses!

zlone

Yesterday, I listened to some favorite music at a friends warmed up tube system with his new to him tube preamp. Sounded great, different and we both think better than before, AND he got remote volume and remote balance, Oh Happy Day. That will make anything sound better!

Came home, warmed my system up, did a few things, listened to same music on my warmed up system. Heard great music and the differences of our systems.

Tomorrow, friend coming, I’m gonna wait till he’s settled, turn the system on, wait 2-3 minutes, play the same music (he is also familiar with that music played on my warmed up system), it should be interesting.

the point is, OP said ’casual listening for short time". It’s the content! A special feature ... no way.

Saving on groceries to buy more tubes is a great idea. What if the man already does it ? And what if his reasons have nothing to do with expenses ?

Don’t know about other amps, in the case of my VAC it s advised to give it at least ten minutes to stabilize before listening and forty five minutes is ideal. But it is integrated amp, with power tubes too. Still I would think at least ten minutes for a preamp.

I went with Class A and personally, I don't miss the tubes. I can listen immediately and it warms up in just minutes anyway. Hot even, but not as bad as tubes. You also can up the power for much less cost.

I might get hate mail for saying this, with comments including that Class A doesn't sound like tubes. Which I agree with, they don't sound the same, but I also don't miss tubes. YMMV of course.

Tubes done right have a certain 'glory' in presentation, I don't think it can be replicated by transistors. It is felt in addition to heard.

And speaking of tube power, with the right amp/speakers match, those 60 ultraliear watts that I get feel like more than double. 

Passive mode is by far the worst  for an active gain stage ,you are using the power 

supplies and soundstage imaging and dynamics are better.

The $1k Schiit Freya + is very good for the money,

but not in the league  of  a Aesthetix , or Linear Tube Audio preamp  a truly good

preamp is much better built in every. Respect and is a fully  active gain stage preamp.

Passive mode is by far the worst  for an active gain stage ,you are using the power 

supplies and soundstage imaging and dynamics are better.

The $1k Schiit Freya + is very good for the money,

but not in the league  of  a Aesthetix , or Linear Tube Audio preamp  a truly good

preamp is much better built in every. Respect and is a fully  active gain stage preamp.  If you have to worry about the expense of  a quad of tubes then  just just save for a good solid state preamp and be done with it .Myselfonlyuse matched vintageNOS tubes  far better then todays Russian,and china tubes, and last much longer ,if bought from a reputable dealer.like Brent Jesse audio,who offers a 2 year 

warranty for little money, or vintage tube services.

Your speaker coils need the 20-30 minute warm up more than the tube amp or pre amp......According to Steve Deckert ( who knows something about sound)

My PrimaLuna amp won't allow me to switch between triode and ultra-linear until the tubes are sufficiently warmed, and my Vincent hybrid preamp has a flashing red LED in the volume knob that goes out when it's ready to play. If those time spans are good enough for the much more knowledgeable people who designed the equipment, I trust their judgement. 

Two issues come into play: 1. My preamp uses four 6H30 tubes (and two tubes which I assume are rectifiers). It’s very hard to acquire GOOD 6h30 tubes these days so, until Western Electric can clone 6H30-DR (Russian mil-spec and the best I’ve heard), I’ve got to conserve. 2. I worry about the thermal effects doing damage over time. I’m also retired and trying to live off only SS. I’m also Scottish who are known to be somewhat "thrifty" so that comes into play. It would just be nice to have the option to NOT burn tubes if I’m going to bed in 20 minutes but want to hear some tunes.

Life is too short. Flip on the tubes and enjoy your system.

Your system is going to sound darn good 2 minutes after you turn it on. Try it. Play something favorite, involving I bet. Wait 30 minutes, play again. How much ’More’ involving?

This is my experience. This problem is a "non-problem." For me.

Now, my Pass XA 25 sounds better at least an hour and maybe 3 after warm up. Much better.

Well, maybe you need an inexpensive transistor preamplifier for that to complement you tube one. Just switch the cables, it's quick and easy.

Life is long enough to spectacularly screw it up.

Life is long enough to spectacularly screw it up.

@inna Heh heh. Good one. I’m clearly a work in progress with much downward potential.

I've heard "Life is what you make it" but I never got the instruction manual.

I have an original version Freya and have never worried about its warmup time and I listen to the tube section exclusively. I like the fact that it doesn't turn off the tubes when I switch to one of the passive settings as its a great way to see if the tube stage is getting tired...instantly. Also, I still haven't found any remarkably better preamp at any price (I've owned some great preamps, and compared my Freya to various other things)...to claim it isn't as good as other more expensive stuff make no sense to me...its considered Class A to many.

Freya+ gives you the tube/no tube (buffer or no buffer w/o tubes). Pro-Ject Pre Box RS2 Digital also has a selectable tube preamp output (along with 2 DACs and a headphone amp)

rcm1203

Most short delays at startup are built-in safety checks, my McIntosh SS Amp, mc2250 had a test sequence; My Cayin Tube Integrated AT88is like yours, nothing possible for 30 second check; and my Little Luxman Tube Integrated has a 30 sec test.

Do they advise waiting 10, 20, 30 minutes for warmup in their manual: NO. 

Do we go with the well touted warmup concept, YES

Use your ears, it would be nuts to deny yourself some casual short time listening to some enjoyable content for lack of warmup.

...............

My friend had car trouble, he will come next week.

My Conrad Johnson Premier 14 preamp came with exactly that sort of stand-by - the tubes are not active until you unmute it.

Having a hard time seeing the use case here. Tubes are designed to get up to optimal temperature very quickly - that’s what the "heater" is for. Transistors can be a very different (and frustrating) story on this front, plus they overheat easily and behave VERY poorly in those conditions. A couple minutes in, and your tubes are good to go.

If you’re entering a several-hours stretch where you want to do several short sessions, just leave it on for that stretch. Or turn it on/off a few times. The tubes will be fine.

If you tally a lot of hours a year and don’t want to pile that onto rare NOS tubes, then the Russian tubes these days are quite excellent.

The Rogue Apollos had a "standby" switch which cut down the high voltage rails while leaving heaters on, but that was specifically for the power tubes (not pre tubes) and even then I hardly ever felt a need to use it.

I start listening right away, and the amp and linestage sound very good within a few minutes; I don't fret over whether the sound is at any sort of absolute peak.  But, I do know someone who complained about the sound of his amps and how long they took to warm up.  The dealer/builder of these custom amps could not figure out why they were failing to please the customer until he heard the amps in the customer's home, under the owner's listening conditions.  It turned out that the owner only listened for short periods and would turn the amps on and immediately start to listen, while the dealer/builder kept the amps on all day.  The issue wasn't tube warmup, it was the capacitors used in the amps.  The amps had Blackgate capacitors, and when they were swapped out for other capacitors, the warm up became MUCH shorter.  It turned out that Blackgates take a very long time to warm up and stabilize.

I have the same sort of issue with my music server which is a solid state unit.  The manufacturer recommends leaving it on all of the time and claims it does not sound its best until about 24 hours after being turned off for a few hours.  This has to do with the capacitors in the power supply of the unit.  

Hmm I might strongly consider another tube preamp that allows me to bypass those sometimes PITA tubes. Good to know. 

mulveling, I thought tubes didn't like on/off cycles. 

I wait for 30-45 minutes after turn on. Do I hear a difference ? YES !  First ten minutes is no go, after that you can go but better wait a little longer. Tubes or capacitors or both, it's exactly as VAC recommends.

Yeah, reissue tubes if you must save.

mulveling, I thought tubes didn’t like on/off cycles.

@inna Maybe, if you turn gear on/off a dozen times every day. Who does that? Or if your component slams full voltage on plates immediately, before heaters have a chance to bring cathodes to temp - but again, who does that? Most hifi gear has some kind of soft-start consideration.

Most small tubes are pretty robust and will outlive our interest in them :) A few duds will emerge, that’s just the way of these things. We audiophiles generally over-worry about tube life & care, IMO. I’ve stopped worrying about it so much, and just turn a tube component on when I want to use it. I have not noticed significant changes in warmup with tube gear (unless it’s a hybrid with transistors in there), but don’t discount maybe some cap or resistor might prefer to be toasty. But I think generally you want to minimize heat on those components - especially electrolytic caps (like 10-years OOP BlackGates)!

For all the concern over tube life, the great thing is you can always replace them! A high end amp using OOP transistors might be SOL unless your manufacturer stocked up well (and is still around to service). Transistors are far from immortal, and in fact they can be a LOT more sensitive than tubes to over voltage and overheating conditions. 

I have found the warm up time required to sound the very best is highly dependent on the make and model. For instance the Audio Research Reference 5 and SE had a very distinct ~ 10 - 12 minute warm up sound improvement… but a signal going through it was required! It was very distinctive… you could turn it on for an hour but the sound improvement happened ten minutes after a signal got sent through it. I thought I was nuts, so I got on a forum… and I was surprised to find detailed discussions about this exact behavior.

Now with the ARC Ref6se… no notable change from the moment the one and a half minute internal warm up and the auto mute comes off.

Other equipment has been different. But an individual piece tends to be completely repeatable.

To my needs experience,  solid state stuff needs much more warm up time than tubes stuff which sound already fine after a few minutes of warm up.

Agree, In my limited experience SS requires longer warm-up time to sound best. 

I turn my Avatar on once a day and turn it off once a day, with rare exceptions. I don't like burning tubes for nothing but it appears that I do it. I feel better about this than about multiple on/offs a day. Terrible for ecology, I know, but I compensate with other things.

I just leave my tube preamp and tube DAC on all the time, unless I'm away for more than a day or during thunderstorms. I have no problem with tube life.

@invalid 

Definitely that can be true. But is somewhat dependent on the specific equipment. 

I suspect both your pieces of equipment have solid state power supplies and tube amplification. Tube power supply life tends to be much shorter than the main circuit tube life. Many older preamps had tube life over 10,000 hours, they never had tubed power supplies. 

@ghdprentice  both my pieces of equipment have tube rectified power supplies, no solid state devices in the power supplies.

I often advise getting your own tube tester.

All my tubes, preamp; rectifier; power: take less than 30 seconds to warm up to measure their strength. Wait another 30, another minute, no change, i.e. they are ready to go pretty darn quick.

Perhaps as others have said, it is other internal parts that benefit from longer warmup. 

In any case, for a quickie 20 minute listen, turn it on, play the chosen content, MOST tube amps will sound darn good. it's the chosen content that will take you there.

@invalid

Thanks for your reply. Really. That means you are running them 8,700 hours a year.

I have been told that tubes… particularly power tubes age more slowly when on but not in use. Maybe that has something to do with it.

My Audio Research gear recommends tube changes after 3,000 hours. When I do this I hear a bit of and improvement, as in the older tubes were starting to roll off a little.

What kind of gear do you have?

@ghdprentice  power tubes do age faster, but those are in the output stage of an amplifier, not in the power supply section usually, though some power tubes can be used as rectifiers and in some regulation positions.

@invalid 

That makes sense the lasting longer would not extend from power tubes to rectifier and smaller tubes.

So, what is your preamp / DAC.

@ghdprentice my preamp is space tech Lab qa112 and my DAC is also space tech Lab DA24/196, I'm using a separate power supply with the preamp called a super rectifier STR104 with two 3b22 rectifier tubes each rectifier tube has a 6amp heater current.

Thanks. Interesting. I had not heard of them. Lots of tubed equipment. They must use the tubes conservatively to get so much mileage out of them. Always good to see different audio companies.

Your speaker coils need the 20-30 minute warm up more than the tube amp or pre amp......According to Steve Deckert
 

Very interesting. Never heard of that before. And I am not saying this with any sarcasm.

Speaker coils? Hmmm...my Freya sounds great as soon as the tubes warm up and my Pass XA-25 takes maybe an hour or so but sounds so good immediately you sort of forget that. I wouldn’t think about that if Nelson hadn't mentioned it in the manual. I sometimes swap out the Pass for a Dennis Had Firebottle SEP tube amp that seems to sound great immediately, and If the speakers coils are cold you need a warmer room. Preheat ’em with a heat gun...knit them a cozy...a hug...some tea...insults...

I just hooked up my super tube rectifier to my space tech lab preamp. What a difference! It made everything sound a level smoother refined all of the same time. I was a little leery about the whole thing but it was definitely worth the $1100. Amazing. The part that concerns me is that I don’t believe in power cord or interconnects or speaker cables making a difference from what I’ve read the rectifiers are supposed to make a difference. Anybody out there explain to me what these super two rectifiers do that have such a positive  Influence on the Sound quality?